The present invention relates to a method for producing a bundled fiber.
Bundled fibers are classified into those functioning as image guides for transmitting images and those functioning as light guides simply for transmitting optical energy. In an image guide for image transmission, the positions of elemental image fibers as picture elements at the incoming and outgoing ends should exactly correspond to each other in order to minimize distortion of the transmitted image. On the other hand, a light guide does not always require such an arrangement because it is only intended for transmission of light energy.
The present invention pertains to a method for producing an image guide for transmitting an image. Production methods for bundled fibers used as image guides appear to be classified into a winding method, a foil stacking method, multifiber formation, and fiber plate formation as described, for example, in the Journal of the Society of Electric and Electronics Engineering, Japan, Vol. 97, No. 11, November 1977. In prior methods suggested for producing image guides, although they individually have both advantages and disadvantages, none simultaneously meets all of the requirements upon the number of picture elements, the producible length, and the flexibility of fibers.
It is thus an object of the invention to provide fiber bundles for an image guide having a length of from several kilometers to several tens of kilometers with the resulting fiber bundle having a good flexibility and a sufficient number of elemented image fibers or picture elements.
Furthermore, it is an object of this invention to provide image fibers in which the transmission loss of an elemental image fiber for each picture element can be reduced to 10 dB/km or below by selection of an appropriate matrix for the picture elements. When compared with conventional fiber bundles, a markedly improved transmission distance for an image of a predetermined brightness is desired. Moreover, in view of the characteristics of the fibers used as a picture element, images from the ultraviolet to the infrared regions should be capable of being transmitted, and, as a result, the range of application for such fiber bundles is to be broadened.